Hydrogen - linde-engineering.com

1 Hydrogen 3 Introduction 4 Hydrogen 6 Production of Hydrogen from light hydrocarbons 8 Process features 10 Process options 13 Modular Hydrogen plants 14 Liquid Hydrogen technology 16 - the company s backgroundin the Hydrogen since Hydrogen was in demand in the chemicaland fertilizer industry and more recently in the petro-chemicals field Linde was involved with the latest improvements in Hydrogen generation. For example, the purification of various industrial raw gas feed-stocks like coke oven and coal gasification gases,sophisticated and tailor made sourgas steps with chemical and/or physical absorption, and adsorption steps followed by low temperature purification and rectification processes with cold box demand of Hydrogen grew as the world s consumption of refinery products increased by the ever growing demand for better and more abundantautomotive fuels called for better yields fromthe limited feedstock crude oil.

2 In turn thedemand for Hydrogen import grew to balance the Hydrogen refining catalytic refinery process all Hydrogen technology suppliers, Linde is the outstanding contractor for complete Hydrogen plants and the only company who owns all technologies inhouse, covering the complete range of petrochemical feedstocks from natural gas through LPG, refinery off-gases and naphtha up to heavy fuel oil, asphalt and coal. These technologies are basically: Steam reforming technology for light HC-feed- stock combined with Linde s own PSA systems for Hydrogen purification. Partial oxidation technology for heavy HC-feedstock followed by a sequence of various integrated process steps to shift, desulfurize and purify the raw Hydrogen . The pure oxygen for the gasification is produced with a Linde air separation plant in specific Linde know-how in all these fields are the essential advantage for a successfulintegration and complete inhouse optimizationof all process sections.

3 The results are highlyefficient and reliably operating Hydrogen the early 70 s Linde favoured and promo-ted with innovative improvements the now well established steam reforming/pressure swing adsorption technology for the production of pure and ultrapure Hydrogen preferably from light hydrocarbon know-how in design and constructionof furnaces, steam reformers and heaters has been completed with the acquisition of Selas of America, which is now Selas Fluid Processing Co. in the USA and SELAS-LINDE GmbH in Germany. Linde together with Selas have developed their own proprietary top fired reformer the know-how of the Engineering Division and the Gases Division the company is in the unique position to build, own and oper-ate complete Hydrogen plants for continuous supply of Hydrogen over the fence to large re-fineries and chemical companies.

4 The extensive feedback of operating data and information on process and equipment performance in oper-ating plants provides Linde with substantial background for the yet more efficient designof future than 200 new Hydrogen plants have been built all over the world, for clients in the refining, chemical and fertilizer industry, with capacities ranging from below 1,000 Nm3/h to well above 100,000 Nm3/h, and for processing of all types of feedstock. Most of these plants have been built on a lump-sum turn-key plant in Australia5 Linde has a well-proven technology forhydrogen manufacture by catalytic steamreforming of light hydrocarbons in combi-nation with Linde s highly efficient pressure swing adsorption typical flowsheet for a Linde designed large capacity Hydrogen plant is shown in figure basic process steps1.

5 Hydrodesulfurization of feed stock2. Steam reforming3. Heat recovery from reformed and from combustion flue gas to produce process and export steam4. Single stage adiabatic high temperature CO-shift conversion5. Final Hydrogen purification by pressure swing adsorptionFigure 1 Demin waterFeedFuelExport steamHydrogenH2-recyclePurgegasSteam ProcessWaste heatrecoveryFeedpretreatmentSteamreformi ngCO-shiftconversionPressure swingadsorption6 Production of hydrogenfrom light reformer7 Process design and optimization for every process step and in particular the optimized linking of operating parameters between the two essential process steps: reforming furnace and pressure swing adsorption unit are based exclusively on Linde s own process and opera-ting know-how. Commissioning and start-up of the plants as well as operator training and after sales service are performed by experienced reformer furnaceA compact fire box design with vertical hanging catalyst tubes arranged in multiple, parallel number of forced draft top-firing burners, integrated into the firebox to other designs, burner trimmingand individual adjustment to achieve a uniform heat flow pattern throughout the reformer cross section is substantially firing ensures a uniform temperature profile throughout the reformer tube length.

6 Flame and stable combustion flow pattern is supported by the flue gas collecting channels arranged at ground level between the hot re-formed gas headers. Thermal expansion as well as tube and catalyst weight are compensated by the adjustable spring hanger system arranged inside the penthouse, removing the mechanical stress from the hot manifold outlet headers at ground radiant reformer box is insulated with multi-ple layers of ceramic fibre blanket insulation, me-chanically stable and resistant to thermal sectionDepending on the Hydrogen product capacity, the convection section - a series of serial heat exchanger coils - is arranged either vertically with ID-fluegas fan and stack at reformer burner level or - specifically for the higher capacity units - horizontally at ground level for ease of access and reduced structural airFeedLP steamDemin waterHP steamHydrogenProcess plant in ChinaPressure swing adsorptionThe particular features of Linde s PSA technology are high product recovery rates, low operat-ing costs and operational simplicity.

7 Excellent availability and easy monitoring are ensured by advanced computer control. Extensive know-how and engineering expertise assisted by highly sophisticated computer programs guarantee the design and construction of tailor-made and economical plants of the highest quality. Modular skid design of the PSA plants reduces erection time and costs at site. The fully prefabricated skids are thoroughly tested before they leave the workshop. Smooth operation to protect catalysts and reforming tubes require a thorough feedback from the internal PSA computer system regarding purgegas flow and heating value. This enables the control system to control the furnace s total fuel management in dependence on the final Hydrogen product philosophySafety (Hazop-) studies and ESD-system design philosophy are based not only on more than30 years of steam reforming plant experience but on the cumulative know-how, which the Linde safety experts gained with numerous turn-key lump-sum contracts, especially for large-scale synthesis gas plants as well as for complex olefin production protectionFor steam reforming based Hydrogen plants, special care is taken regarding gaseous emission of NOx and CO, calculation of outdoor sound propagation and measurement of noise emission design, design of blow-down and flare system, considering permissible levels for heat radiation and air pollution is the term applied to the low temperature steam reforming of hydrocarbons in a simple adiabatic reactor using highly active, nickel based catalyst.

8 Which promotes the steam reforming reaction at low temperatures. This process was developed in the 1960 s for town gas and synthetic natural gas (SNG) - ranging from natural gas to naphtha is converted by the steam reforming reactionto give an equilibrium mixture containing Hydrogen , carbon oxides, methane and steam. Depending on the feedstock, the temperature profile can be either endothermic or exothermic. The advantages provided through the inclusionof a pre-reforming unit may often be plant specific. Some or all of the following advantages may apply to a specific case Fuel savings over stand alone primary reformer Reduced capital cost of reformer Higher primary reformer preheat temperatures Increased feedstock flexibility Lower involuntary steam production Lower overall steam/carbon ratios Provides protection for the main reformerIn its most common application today the main benefit comes from the ability to effectively transfer reforming heat load from the radiant section of a reformer to its convection feedgas and steamMixed feedpre-heatPre-reformerre-heatPre-refor merReformed gasPrimary reformerProcess from the conventional adiabatic MT-shift, Linde developed and successfully installed the isothermal Medium Temperature shift reactor.

9 A fixed bed reactor suitable for exothermic and endothermic catalyst reactions, with an inte-grated helically coiled tube heat exchanger for cooling or heating of the the case of isothermal MTS the exothermic catalytic reaction heat is removed by producing steam, with only a few degrees of temperature difference throughout the reactor. This isother-mal reactor type is successfully applied in the chemical industry for the methanol synthesis,for methanation, hydrogenation and for the Linde CLINSULF sulfur heated reforming (GHR)The GHR unit is a combination of a gas heated reformer and an oxygen-fired autothermal reformer, where the heat of reaction is supplied by the hot gas exiting the autothermal main advantages of the GHR process: Lower energy consumption Lower investment costs Primary reformer with flue gas waste heat recovery system is eliminated No steam production in the reformed gas cooling section, thus eliminating the waste heat boiler As steam/power generation and oxygen pro- duction are confined to independent units.

10 Opportunities exist for over the fence supply Optimum consideration of environmental aspects with regard to zero flue gas from the core unit and relevant minimum charges originating from the potential power/steam generation unitThe convective as well as the autothermal step can be individually integrated in flow schemes for revamping and capacity increase of existing conventional Hydrogen gas /steamOxygen / steamSyngasGas heated reformingIsothermal reactorSteamBoiler feed waterGas entryCirculating waterGas exitCirculating waterReformer furnace Natural gas LPG Naphtha Refinery gas Product flow rate Nm /h 50,000 50,000 50,000 50,000hydrogen MMSCFD pressure bara purity mol-% Export flow rate T/hr 31 temperature C 390 390 390 390 pressure bara 40 40 40 40 Feed and fuel Gcal/hr GJ/hr Energy consumption Gcal/1,000 Nm H2 (incl.)